21015130 has 8 divisors (see below), whose sum is σ = 37827252. Its totient is φ = 8406048.

The previous prime is 21015119. The next prime is 21015139. The reversal of 21015130 is 3151012.

It can be written as a sum of positive squares in 2 ways, for example, as 19829209 + 1185921 = 4453^2 + 1089^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 21015130.

It is not an unprimeable number, because it can be changed into a prime (21015139) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050747 + ... + 1050766.

Almost surely, 2^21015130 is an apocalyptic number.

21015130 is a deficient number, since it is larger than the sum of its proper divisors (16812122).

21015130 is a wasteful number, since it uses less digits than its factorization.

21015130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2101520.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 21015130 is about 4584.2262160587. The cubic root of 21015130 is about 275.9586597047.

Adding to 21015130 its reverse (3151012), we get a palindrome (24166142).

The spelling of 21015130 in words is "twenty-one million, fifteen thousand, one hundred thirty".